Rules of an Angel
by kiwismakemehappy
Summary: Because someone has to keep Sherlock Holmes out of trouble, and it might as well be an old army doctor. Guardian Angel AU.
1. Chapter 1

_A/N: In my head cannon, John is equal parts kind caretaker and BAMF, so it stands to reason that he would be a prime candidate for guardian angel duty! This story has been bouncing around in my noggin' since viewing episode one, so I'm finally giving it life. Also, you should be aware of the fact that I'm pretty busy, so whether or not I continue this story is completely up to reader feedback. Aaaaand that is all. Enjoy!_

_Disclaimer: The Sherlock Holmes books and all of their various incarnates are not mine, and I am in no way attempting to claim them as such. This story is a work of fanfiction not intended for any sort of copyright infringement. _

When John Watson was first assigned to Sherlock Holmes, he assumed that there was some sort of mistake.

He was fresh from his "deployment" as a guardian for Victor Trevor, a soldier shot through the heart in Afghanistan. That was the thing about being a guardian angel—you might do everything right, and it still wouldn't be enough if it was a person's time to die. John had liked Victor. He was young, affable, and incredibly brave. John had subtly helped the young soldier through the various hazards of his two year deployment, only to have his assignment end when Victor saved almost two dozen men from friendly fire by sacrificing his own life.

John watched miserably as the young man was pronounced dead, and followed him back to London like a silent sentinel. He skipped the funeral, where he knew that the twenty-two year old's single mother would be, because he didn't think he could handle her grief.

For the past two hundred years, John had specialized in guarding soldiers. As both a doctor and a ex-military man himself, he had a unique ability to be a ferocious protector while still remaining emotionally detached enough to do his job for years on end. So when his gate keeper informed him upon his return that his next assignment was a young genius drug addict, he was surprised and a little shaken.

"Did I do something wrong?" He asked, sure that this was some sort of cosmic punishment. He was a soldier and a doctor, not some sort of social worker. He was ill-equipped to babysit a self-destructive, over-grown child.

John's expression became one of intense remorse as he thought of his previous charge. "Was it Victor? Could I have saved him?" He demanded.

The gatekeeper only smiled kindly.

"Perhaps," he said cryptically. "But then, the men he died protecting would surely have perished. You did everything you should have, and it is not our place to rob mankind of their ability to choose their own fate." There was a significant pause as the gatekeeper across from John chose his next words.

"No, John, you did not fail. You have been called in because I think you can succeed where no one else has. Your charge, Sherlock Holmes, is a key player in upcoming events that will touch millions of lives. As things stand now, however, he is at the edge of a very steep precipice. He needs someone to guide him in the right direction. I am sure that you would do well in this position"

John knew he should be flattered, but it did nothing to abate his trepidation.

"Why me?" He asked. "Why not send one of the others? I'm not really a patient person, and it's not like I'm smart enough to operate on his level. I'm probably the worst guardian you could have chosen."

"On the contrary, I think you are exactly the person I'm looking for," the heavenly being replied- kindly, but with a note of finality. John wanted to argue, but he knew that it would be futile at this point. For better or for worse, he was officially Sherlock Holmes's divine caretaker. The doctor nodded his assent, and stood up to leave. As his hand touched the doorknob, the gatekeeper spoke up one final time.

"Oh, and John? I've reviewed your file, and I think you've served long enough. This is your last assignment before you move on, so make sure you have no regrets."

The doctor's eyes widened in surprise and he considered the implications of that statement. Still, John knew that he wasn't expected to reply, so he merely nodded to show that he'd heard and continued his journey out into the blinding London sunlight.


	2. Chapter 2

Now that he had an assignment, John's sixth sense kicked in and urged him toward his new charge. He walked up Camden and then took the tube to West Ham. He followed his gut down winding roads and shady alleys. Soon he was in a bad part of town, with hard looking men slouching against cars and especially vulgar graffiti defiling everything within an arm's reach. The air reeked of exhaust and urine. In an adjacent drive a man wrapped in newspapers convulsed in obvious pain.

John took it all in and did his level best not to jump to conclusions. Sherlock could be here for any number of reasons. Perhaps he was visiting a friend or passing through the area. Being in the worst part of London didn't necessarily mean he was involved in anything... unsavory.

Then again, men living perfectly safe and well-adjusted lives hardly needed guardian angels watching their backs.

The road stretched on for another few blocks, but John took an abrupt right turn instead. His internal compass, instead of pointing north, pointed to Sherlock, and deep in his bones he could feel the man was somewhere near. He passed an industrial-looking door and felt compelled to stop. He tried the handle, only to realize that it was heavily barred with a padlock. John sighed- He hated picking locks.

"You lost mate?" asked a raspy voice somewhere to his right. An old man with a few years' worth of facial hair and more layers of clothing then were strictly necessary shuffled out of the shadows. John did his best not to react.

"No, just looking for a friend" John replied, attempting to look insignificant and nonthreatening. At 5' 7" tall and bundled up in a woolen jumper, it wasn't particularly difficult.

"Isn't we all?" the man said, letting out a braying laugh that quickly turned into a painful hacking cough. John waited patiently for him to finish. When the old man was only wheezing and gasping, John pulled a water bottle out of his rucksack and handed it to him. The homeless man guzzled the drink, letting wet rivulets escape out of the sides of his mouth and down into his beard. He soon finished the bottle with a satisfying smacking of wet lips.

The old man looked at John closely and narrowed his eyes. "What you really doing here? Clean guy like you, prolly have a missus and little baby waiting at home."

Outwardly, John smiled blandly, but a spear of heartache sliced though him as he thought of darling Mary and little baby Madeline. Over one hundred years had barely dulled the ache.

"My friend is probably in a trouble, and I mean to help him," John replied.

The man seemed deep in thought.

"Don't seem like no cop. Cain said no coppers, let nobody through, but he's jus' a man in a jumper. Just a man…"

"My name is John," the good doctor said hopefully. He was becoming progressively more nervous with each minute that he was separated from Sherlock. Warning bells were sounding in the back of his head, and he knew that his charge was in desperate need. If this old man didn't let him though, he would have to put him to sleep and pick the lock, neither of which appealed to him.

Luckily for both of them, the impromptu guard nodded his head sagely and shuffled to the door. "Couldn't do no harm," he mumbled, and unlocked the giant padlock separating John from his new charge.

"Thank you," John replied warmly, and took off at a brisk walk into the depths of the building. It must have originally been some sort of office space, but now it seemed to be the final resting place of a number of boxes and useless ends. The angel paced from one end of the building to another, finding nothing but rats and rubbish.

'Where is everyone?' he wondered, trying valiantly to pinpoint Sherlock. He was so close, almost as though he was in the very ground…

'Ah!' he realized in a moment of clarity. 'There must be a basement.'

Two precious minutes of searching revealed an unlit staircase. "'We are call'd–we must go/Laid low, very low/In the dark we must lie,' he muttered, and with that grim thought descended into the cellar."

The farther into the basement John traveled, the more uneasy the angel felt. The building was an obvious drug den, with prone bodies strewn about and people doing unmentionable things in corners. It had been half a century since he had been paired with a civilian— and while he was more or less inured to the perils of war, witnessing this spiral of self-destruction was raw and painful.

As shocking as everything was, the doctor could not muster up revulsion or scorn—all he felt was worry for his charge, and the intense need to find him right _now_.

John flung open the door at the end of the hallway and bit back an exclamation when he saw the room's occupant. Sherlock—because John knew it was Sherlock, could feel the recognition zinging through his bones like an electric charge— was draped across a ratty divan like some sort of tragic Greek hero. The man was tall, striking, and obviously ill, with a band tied around his upper arm and bruising decorating the inner crook of his elbow. Diagnostics whirred through the doctor's mind.

"Long-time user. Gaunt, pale, obviously brittle nails. Cold sweats and tremors. Vomit on the floor." John stalked forward and put a practiced hand on his charge's pulse. "Erratic heartbeat, and quick, shallow breathing. Overdose. Damn."

"Hey there Sherlock. Are you awake? Can you hear me?" John asked. When that didn't get a response, John reached forward to check his newfound patient's pupils. Without warning, long, pale fingers snatched his hand away.

"Afghanistan or Iraq?" demanded a deep baritone that was dry with disuse.

"Excuse me?" John demanded, flummoxed. Sherlock's eyes snapped open and pinned John in place with their fever-bright intensity.

"Your posture shows that you are obviously fresh from extended military service and wearing a jumper in the middle of the summer, which indicates an acclimation to desert conditions, most likely Afghanistan or Iraq." The statement came out in a muddled rush, but John could make out the gist of it. "I deduce Afghanistan. Your beside manner and the callous on your index finger also identify you as a doctor. So you are left-handed army doctor fresh from Afghanistan that feels particularly uncomfortable in this _establishment_," Sherlock spat the last work, and then relinquished John's hand as if it was something dirty.

"Why are you here? And how do you know my name?"

"It's not important. You're going to be fine, everything is fine."

Sherlock opened his mouth to retort, or to deduce, or to insult, but he never got the chance. He was suddenly raked with a seizing pain that sent him tumbling off of the chair. He tried to breath, to think past the pain, and he simply could not. He sucked in one strangled breath after another, but it did him no good. Black spots danced around in his vision. 'The oxygen,' he thought, 'someone has stolen it all.' And then he laughed at the absurdity of his thought. Except that he wasn't laughing, he was choking, and damnit, _damnit_ he hurt.

John sprang into motion and started treating his struggling charge for cardiac arrest. The next few minutes were a blur of panic and chest compressions. John managed to bully a young addict into calling an ambulance as he tried to stabilize Sherlock. Within minutes help arrived, and John stepped out of the way to let the paramedics load the genius onto a stretcher.

As the ambulance left the scene and the Yard began to swarm the drug den. John managed to slip away—one of the perks of being a guardian was the ability to blend into crowds—before he could be questioned. As he watched the chaos unfold he thought about Sherlock: on the verge of death and still reading John with crystal clarity. If his mind was so astute under those circumstances, the doctor could only imagine what his charge was capable of with a full bill or health.

"What the hell have I gotten myself into?"

_A/N: Yippeeee! A special thanks to everyone who has reviewed, favorite, or alerted so far. I would not have struggled though this chapter if not for you. Hopefully this was worth the wait._

_Disclaimer time: I own neither Sherlock nor the poem "All Things Will Die."_

_I have never been to London. So if you were paying attention and the geography seems wonky… goggle maps only shows so much. Also! I am not a doctor, and I probably botched up what an overdose/cardiac arrest looks like. Feel free to drop me some concrit! (Or flames—those are my favorite.)_

_Over and out!_

_~Kiwis_


	3. Chapter 3

John's first few weeks as Sherlock's guardian were touch and go- he spent more time then not crouched outside of Mycoft's manor, prepared to alert the government official by subtle means whenever his wayward younger brother decided to make a bid for freedom. Sherlock attempted to escape on four separate occasions, the last time being the most creative involving six hundred pipe cleaners and an impromptu fire alarm.

Still, by the end of the week, Sherlock was in no state to do much of anything, let alone break out of one of the most secure houses in Europe. Even from his place on the edge of the grounds John heard his charge's agonized battle with his painful withdrawal symptoms. As a doctor, John had seen many similar cases, and he knew the stages Sherlock would pass through before he was fully clean. He also knew that as well-meaning as Mycroft Holmes might be, no one would be able to break Sherlock's addiction but Sherlock.

Unfortunately, the genius had no such plans. Sherlock craved stimulation, and the drugs certainly supplied it. John had only known the man for a few days and it was obvious to the guardian that Sherlock needed something to keep his mind from spinning out of control and tearing itself apart from sheer boredom. So on the eighth day, when he knew that Sherlock would be too miserable to try anything, but far enough into the withdrawal process that he was out of any immediate danger, John Watson made a trip to Scotland Yard.

"Hullo Mike," he said, greeting his heavyset doctor friend with a smile. Mike Stamford had become a guardian angel within twenty years of John, and the two men had been assigned to twin brothers in Vietnam. Stamford was a reliable, friendly chap, and John enjoyed meeting up every so often.

His old friend cried out in surprise and clasped John's shoulder with a meaty hand.

"Well, I'll be! John Watson! Last I heard you were stationed in Afghanistan with a boy getting shot at. What brings you here?" Stamford asked, and John did his best to remain docile, shrugging as nonchalantly as he was able to.

"He got shot."

Stamford grimaced. "Sorry."

"Yes, well, he was a good soldier. Much braver than either of us," The angel replied, giving his friend a wry grin. John wasn't the only one to take the so-called coward's way out. He continued.

"I've been reassigned."

"Already? You'd think the afterlife would be more of a picnic, wouldn't you? Well, if this bit is limbo, then I'm interested what heaven will actually be like," Stamford said, and John snorted.

"I'll see soon enough—this is my last assignment before they pass me on to whatever's next," he replied, doing his best to be offhand about the news. Of course, Stamford saw right through the act, and gave his friend a hearty slap on the back.

"Well congratulations! I can't believe it's finally happening," he replied, smiling hugely, his eyes crinkling behind thick spectacles. When John didn't elaborate further, Stamford realized there was more to the impromptu visit then merely catching up on their non-lives.

"So what brings you to my neck of the woods? Is this about your new assignment?" he asked, and John inclined his head in response.

"Yeah. He's in a bad state right now, but when he's better I was wondering if there was any way you could influence your chap to hire him or something," John suggested, not exactly sure if Mike's charge— Lestrade, John thought his name was—had any sort of pull when it came to providing jobs for genius ex-cocaine addicts, but it was worth a shot. Mike whistled through his teeth, seemingly deep in thought as he pondered the odd request, and John's heart sank a bit.

"Well, that depends on a few things. Greg's incredibly practical. He'd never hire someone just for the hell of it. What is different about your bloke that makes him so special?"

"He's bloody brilliant," John asserted, thinking about the intensity of Sherlock's stare as he accurately guessed half of John's life story, even on the brink of overdose-induced death. "He can see more about people from a quick glance then I could after spending a month with them." John frowned and continued. "Of course, his brain is almost more than he can handle sometimes, and he's completely impossible to deal with. It wouldn't be a matter of Sherlock being useful to the Yard so much as the Yard being able to stand working with him."

Despite himself, Mike was intrigued.

"Really? Greg's in charge of some of the most aggravating individuals on the force and it doesn't seem to bother him much. No matter how much of an arse this Sherlock character is, my boy can handle him," the angel said with pride.

Something deep down inside of John broke a bit at his friend's tone— if Greg Lestrade was anything like Mike had portrayed him, then the yarder was a man in a hazardous line of work, work made all the more dangerous by his dogged determination to do the right thing.

Attachment was a precarious thing when you were dealing with such fragile lives. For Mike's sake, John hoped that the DI wouldn't meet the same unhappy fate as many of his predecessors. Instead of killing the mood and reminding Mike about the importance of rule number three, John cleared his throat and let a devious smile light up his face.

"Sherlock might give him a run for his money," he said, hoping the old teacher would take the bait.

He wasn't disappointed.

"Is that a challenge?" Mike asked, his eyebrows up near his hairline and his face breaking into a huge grin.

"Only if you think your detective can't deal with my genius," John replied casually.

"Give me two weeks," Mike demanded, "and then send Sherlock to a crime scene. I can't make any promises, but if he's as good as you say he is, Lestrade will hire him."

#~#~#~#~#~#~#

True to his word, Mike planted the idea of a crime-solving genius in a few of Lestrade's coworkers. Within three weeks, and after Sherlock's quick solution to one particularly spectacular case involving a dastardly convoluted inheritance scheme, the DI offered Sherlock a full-time job. "We could use a mind like yours on the force," he said.

John grinned with self-satisfaction. He loved it when a plan came together.

"Absolutely not," the genius replied with a sniff of aristocratic disdain. "You can't be serious."

John almost groaned aloud from where he stood hidden behind a cab. Infuriating son of a...

"Sure I am. You were born to solve crimes," Lestrade said with a shrug. "If you keep clean and at least try to tone down the insults, you could be a proud employee of Scotland Yard."

Sherlock looked as affronted as if someone had said something particularly derogatory about his grandmother.

"Hardly. Being constantly surrounded by idiots, having to take whatever mediocre case that came my way, doing _paperwork_," Sherlock snarled, "all of it sounds like a fate worse than death. _Dull_."

A lesser man would have balked at the insult, but the DI was made of sterner stuff: he merely smiled. "Fine then. But that means that you'll miss out on all the interesting murders," he said in the tone of a parent temping a child with sweets.

"Which is why I am going to be a consulting detective," Sherlock replied, as if the answer was incredibly simple.

This statement caught everyone off guard, including John.

"A what?"

"Do keep up inspector. I am going to be a consulting detective. As such, I am someone you call in whenever the Yard is out of its depth on a case."

The condescending, "which is always," went unsaid, but Lestrade knew it hung silently in the air. Lestrade also knew that he would not say no to Sherlock's demands after seeing him in action. The small part of the yarder that balked at the thought of working with the demanding genius was largely overruled by the possibility of quickly closed cases and the lives that would undoubtedly be saved. Still, the older man refused to give in so quickly.

"There's no such profession," Lestrade countered, and the genius rolled his eyes.

"There is now," replied Sherlock Holmes, and with an abrupt face that made his coat flare out dramatically, he sauntered off into the darkness.

_A/N: Welp, there's part three. (The whole story feels very dry, but hopefully I'll be able to remedy that soon.) The plan is to have some dialogue between John and Sherlock next chapter, so… something to look forward to! Thank you to everyone who reviewed so far! If you have any suggestions or thoughts, please let me know. Also, I'm thinking about writing a one-shot that gives a little bit of background for John and my AU. Yes? No? For goodness sake, stop rambling?_


End file.
